The present invention relates to a method of producing high-frequency modules for use in, for example, portable telephones. Conventional voltage-controlled oscillators (referred to as VCOs, an example of high-frequency modules) are manufactured by a method comprising a first step of mounting electronic components onto a group of sub substrates 2 configured in a uniform pattern and joined to each other on a master substrate 1 as shown in FIG. 17, a second step of separating the sub substrates 2 on the main substrate 1 from each other as shown in FIG. 18 as following the first step, a third step of examining each of the separated sub substrates 2 for its correct function via connection with a power supply and trimming with a laser beam using the inductance of a resonant circuit fabricated in the pattern to determine the frequency as following the second step, a fourth step of covering the sub substrate 2 with a shielding case 3 as shown in FIG. 19 as following the third step, and a fifth step of carrying out a final inspection as following the fourth step.
FIG. 20 is an enlarged view of a primary part of the master substrate 1 showing rows of the sub substrates 2 of a rectangular shape joined to each other on the master substrate 1, both ends of the rows of the sub substrates 2 being linked to connector regions 4 at both edges of the master substrate 1. Signal terminals 5, 6, 7, and 8 are provided on both side edges 10 of each the sub substrates 2. Grounding terminals 9 are provided on the side edges 10 while grounding terminals 11 are provided on both longitudinal end edges 12 of the sub substrate 2. The signal terminal 5 may be connected to a first circuit 13 in the pattern which is then connected by a second circuit 14 to the signal terminal 6 at the other side. The signal terminal 7 may be connected by a third circuit 15 to the signal terminal 8 at the other side. Dummy regions 16 are provided as will be punched off by a punch for defining the side edges 10 of the sub substrate 2. The longitudinal end edges 12 are grooved in V shape for ease of separating the sub substrates 2 from each other.
Such a conventional method, as described above, of fabricating high-frequency modules, namely VCOs, has a drawback in that the sub substrates 2 are separated from the master substrate 1 at the second step and then aligned again for the frequency adjustment at the third step, hence lowering the efficiency of the production process. The present invention has been developed for eliminating the foregoing drawback and its object is to provide a method of producing high-frequency modules at a higher rate of the production efficiency.
For achievement of the object of the present invention, the method of producing high-frequency modules comprises: a first step of fabricating, on a master substrate, a plurality of sub substrates linked to connector regions at both ends of the master substrate, each the sub substrates formed of substantially a rectangular shape and having an identical pattern of circuit developed thereon, providing, on both side edges of the sub substrate, a set of signal terminals connected to a first circuit so that the signal terminals at each side edge are formed integral with other signal terminals provided on the corresponding side edge of the neighbor sub substrate and connected to a second circuit, and mounting electronic components on the sub substrate; a second step of, after the first step, electrically isolating the signal terminals at each side edge of the sub substrates from the other signal terminals at the corresponding side edge of the neighbor sub substrate while the connector regions of the master substrate remain linked to the sub substrates; a third step of, after the second step, conducting a first inspection with pins of an inspection tooling engaged in direct contact with the signal terminals of the sub substrates; and a fourth step of, after the third step, separating the sub substrates from the master substrate by cutting along the longitudinal end edges of each the sub substrates. Accordingly, the productivity for the high-frequency modules will be improved.
As a first feature of the present invention, a method of producing high-frequency models comprises: a first step of fabricating, on a master substrate, a plurality of sub substrates linked to connector regions at both ends of the master substrate, each the sub substrates formed of substantially a rectangular shape and having an identical pattern of circuit developed thereon, providing, on both side edges of the sub substrate, a set of signal terminals connected to a first circuit so that the signal terminals at each side edge are formed integral with other signal terminals provided on the corresponding side edge of the neighbor sub substrate and connected to a second circuit, and mounting electronic components on the sub substrate; a second step of, after the first step, electrically isolating the signal terminals at each side edge of the sub substrates from the other signal terminals at the corresponding side edge of the neighbor sub substrate while the connector regions of the master substrate remain linked to the sub substrates; a third step of, after the second step, conducting a first inspection with pins of an inspection tooling engaged in direct contact with the signal terminals of the sub substrates; and a fourth step of, after the third step, separating the sub substrates from the master substrate by cutting along the longitudinal end edges of each the sub substrates. As the second step is provided for electrically isolating the signal terminals on the side edges of any two adjacent sub substrates from each other, the method can be carried out up to the third step for the inspection using the form of a worksheet. Since the sub substrates are separated from each other after the third step, the productivity will significantly be increased without conducting such a troublesome step as in a conventional method of separating sub substrates and then aligning them again for the inspection.
Also, because the separation of the sub substrates is performed directly at the signal terminals on their side edges, such dummy portions to be punched out as in a conventional method can be eliminated and the loss of substrate materials can be minimized hence contributing to the lower cost of the production.
As a second feature of the present invention, the method of producing high-frequency modules according to the first feature is modified in that the electrically isolating the signal terminals at the second step is implemented by providing slits. This permits any two adjacent signal terminals to be electrically isolated from each other at higher certainty. Also, the electrical isolation is physically implemented thus eliminating such a troublesome process as a cutting of the side edges of the sub substrates by means of the fingers of a worker.
As a third feature of the present invention, the method of producing high-frequency modules according to the first feature is modified in that the electrical isolation of the signal terminals at the second step is implemented by providing grooves. The grooves permit the sub substrates to be isolated from each other only electrically but not physically, whereby the sub substrates, when urged by the pins at the third step, can hardly be deflected by the urging force hence ensuring the reliability of the first inspection of the third step.
As a fourth feature of the present invention, the method of producing high-frequency modules according to the first feature is modified in that, when the pins are moving to engage in direct contact at the third step, their grounding pines are allowed to touch at the earliest and when disengaging, to depart at the latest. This sequence of energization can ensure the inspection at a higher electrical stability.
As a fifth feature of the present invention, the method of producing high-frequency modules according to the first feature is modified in that the first inspection is to inspect a group of the sub substrates at once. This can improve the efficiency of the inspection.
As a sixth feature of the present invention, the method of producing high-frequency modules according to the first feature is modified in that the fourth step is followed by a fifth step of conducting a second inspection and then a sixth step of mounting the finished high-frequency modules on a tape. As the sub substrates have been separated from each other, they are finally subjected to the second inspection. The resultant high-frequency modules can thus be uniform in the performance. Also, the high-frequency modules are mounted on a tape and can thus be fed into a surface-mounting apparatus at a higher speed. The modules on the tape can easily be stored.
As a seventh feature of the present invention, another method of producing high-frequency modules comprises: a first step of fabricating, on a master substrate, a plurality of sub substrates linked to connector regions at both ends of the master substrate, each the sub substrates formed of substantially a rectangular shape and having an identical pattern of circuit developed thereon, providing on both side edges of the sub substrate, a set of signal terminals connected to a first circuit so that the signal terminals at each side edge are formed integral with other signal terminals provided on the corresponding side edge of the neighbor sub substrate and connected to a second circuit, and electrically isolating any two adjacent sub substrates from each other at their longitudinal end edges; a second step of, after the first step, mounting electronic components on each the sub substrates; a third step of, after the second step, electrically isolating the signal terminals at each side edge of the sub substrates from the other signal terminals at the corresponding side edge of the neighbor sub substrate while the connector regions of the master substrate remain linked to the sub substrates; a fourth step of, after the third step, conducting an inspection with pins of an inspection tooling engaged in direct contact with the signal terminals of the sub substrates; and a fifth step of, after the fourth step, separating the sub substrates from the master substrate by cutting along the longitudinal end edges of each the sub substrates.
While the sub substrates are electrically isolated from each other at the longitudinal end edges at the first step, they are electrically isolated at the side edges at the third step. The method can thus be proceeded up to the final fourth step using the form of a worksheet. As the sub substrates are physically separated from each other after the fourth step, such a troublesome step as in a conventional method of separating sub substrates and aligning them again for the test will be eliminated. As the sub substrates are carried in the form of a worksheet up to the final electrical inspection, the productivity will significantly be increased as compared with any conventional method.
Also, because the electrical separation of the sub substrate from each other is conducted directly at the signal terminals provided on their side edges, such dummy portions to be punched out as in a conventional method can be eliminated and the loss of substrate materials can be minimized hence contributing to the lower cost of the production.
As an eighth feature of the present invention, the method of producing high-frequency modules according to the seventh feature is modified in that the electrical isolation of the signal terminals at the third step is implemented by providing slits. This permits any two adjacent signal terminals to be electrically isolated from each other at higher certainty. Also, the electrical isolation is physically implemented thus eliminating such a troublesome process as of cutting the side edges of the sub substrates by means of the fingers of a worker.
As a ninth feature of the present invention, the method of producing high-frequency modules according to the seventh feature is modified in that the electrical isolation of the signal terminals at the third step is implemented by providing grooves. The grooves permit the sub substrates to be isolated from each other only electrically but not physically, whereby the sub substrates, when urged by the pins at the fourth step, can hardly be deflected by the urging force hence ensuring the reliability of the inspection of the fourth step.
As a tenth feature of the present invention, the method of producing high-frequency modules according to the seventh feature is modified in that when the pins are moving to engage in direct contact at the fourth step, their grounding pins are allowed to touch at the earliest and when disengaging, to depart at the latest. This sequence of energization can ensure the inspection at a higher electrical stability.
As an eleventh feature of the present invention, the method of producing high-frequency modules according to the seventh feature is modified in that the inspection at the fourth step is to inspect a group of the sub substrates at once. This can improve the efficiency of the inspection.
As a twelfth feature of the present invention, the method of producing high-frequency modules according to the eleventh feature is modified in that the inspection at the fourth step is conducted by pressing the pins against substantially identical locations on the signal terminals of each the sub substrate and feeding the signal terminals with an electric signal. This allows the sub substrates to be inspected under uniform conditions.
As a thirteenth feature of the present invention, the method of producing high-frequency modules according to the eighth feature is modified in that the third step of electrically isolating the signal terminals at each side edge of the sub substrates from the other signal terminals at the corresponding side edge of the neighbor sub substrate while the connector regions of the master substrate remain linked to the sub substrates is followed by a step of covering the sub substrate with a shielding case. Since the sub substrate is covered with the shielding case, it can be handled with much ease. Also, the sub substrate can hardly be affected by external noises and do not emit any noise to the outside.
As a fourteenth feature of the present invention, the method of producing high-frequency modules according to the thirteenth feature is modified in that the cutting edges of the sub substrate are created by cutting along the slits so as to extend more outwardly than the shielding case. Since the cutting edges of the sub substrate extends more outwardly than the shielding case, any scratching damage to the shielding case caused by a cutting blade for separating the sub substrates from the master substrate can be avoided successfully. Also, in case that an external stress is exerted, it will hardly be transmitted directly to the soldered portion of the shielding case hence creating no cracking.
As a fifteenth feature of the present invention, the method of producing high-frequency modules according to the thirteenth feature is modified in that the cutting edges of the sub substrate are created by cutting along the slits so as to be substantially flush with the sides of the shielding case. As the cutting edges of the sub substrate do not extend outwardly of the side edges, the resultant high-frequency modules can be reduced in the overall size. Also, the loss of sub substrate materials will be minimized.
As a sixteenth feature of the present invention, the method of producing high-frequency modules according to the fifteenth feature is modified in that the sides of the shielding case are more roughed on their surface than the top. As the top side is roughed, the overall surface area of the shielding case can be increased thus improving the radiation of heat. Also, as its roughed surface increases the force of friction, the high-frequency module can be captured and picked up with much ease.
As a seventeenth feature of the present invention, the method of producing high-frequency modules according to the sixteenth feature is modified in that the sub substrates are separated from each other with the use of a rotary blade which is also adapted for roughing the sides of the shielding case. This eliminates an extra step for preparing the roughed surface, hence improving the productivity.
As an eighteenth feature of the present invention, the method of producing high-frequency modules according to the thirteenth feature is modified in that the shielding case is fabricated by punching a sheet of material with dies, bending the sheet in the direction of punching to form bends, and soldering the distal ends of the bends or legs to the grounding terminals provided on the side edges of the sub substrate. The punching forms such burrs on the shielding case as creating a clearance between the shielding case and the grounding terminals. The clearance is thus filled thoroughly with solder due to the effect of capillary action, whereby the resistance to conductivity will be minimized and the bonding strength will be increased. Also, the burrs are formed inwardly of the side edges of the sub substrate, hence minimizing the distance between any two adjacent sub substrates and decreasing the loss of sub substrate materials.
As a nineteenth feature of the present invention, the method of producing high-frequency modules according to the thirteenth feature is modified in that the shielding case is marked down on its top side using a laser beam. The laser beam can apply markings in a smaller area. In addition, the markings applied by the laser beam can highly be resistant to the rubbing of a finger.
As a twentieth feature of the present invention, the method of producing high-frequency modules according to the seventh feature is modified in that the fifth step of separating the sub substrates from the master substrate is followed by a sixth step of mounting the finished high-frequency modules on a tape. The high-frequency modules, when having been separated, are saved on a tape and can thus be loaded to a surface-mounting apparatus at a higher speed. Moreover, the tape can easily be stored.
As a twenty first feature of the present invention, a further method of producing high-frequency modules comprises: a first step of fabricating, on a master substrate, a plurality of sub substrates linked to connector regions at both ends of the master substrate, each the sub substrates formed of substantially a rectangular shape and having an identical pattern of circuit developed thereon, and mounting electronic components on each of the sub substrates; a second step of, after the first step, covering the sub substrate with a shielding case; a third step of, after the second step, separating the sub substrates from the master substrate by cutting along the side edges of the sub substrates. The sub substrates are covered with their respective shielding cases while they are in the worksheet form, which is much easier than a process in a conventional method, hence improving the productivity. Also, since the substrates are covered with the shielding cases, the modules can be handled with much ease. Furthermore, the module will hardly be affected by external noises and do not emit any noise to the outside.
As a twenty second feature of the present invention, the method of producing high-frequency modules according to the twenty first feature is modified in that the cutting edges of the sub substrate are created by cutting along the side edges so as to extend more outwardly than the shielding case. Since the cutting edges of the sub substrate extends more outwardly than the shielding case, any scratching damage to the shielding case caused by a cutting blade for separating the sub substrates from the master substrate can be avoided successfully. Also, in case that an external stress is exerted, it will hardly be transmitted directly to the soldered portion of the shielding case hence creating no cracking.
As a twenty third feature of the present invention, the method of producing high-frequency modules according to the twenty first feature is modified in that the cutting edges of the sub substrate are created by cutting along the slits so as to be substantially flush with the sides of the shielding case. As the cutting edges of the sub substrate do not extend outwardly of the side edges, the resultant high-frequency modules can be reduced in the overall size. Also, the loss of sub substrate materials will be minimized.
As a twenty fourth feature of the present invention, the method of producing high-frequency modules according to the twenty third feature is modified in that the sides of the shielding case are more roughed on their surface than the top. As the top side is roughed, the overall surface area of the shielding case can be increased thus improving the radiation of heat. Also, as its roughed surface increases the force of friction, the high-frequency module can be captured and picked up with much ease.
As a twenty fifth feature of the present invention, the method of producing high-frequency modules according to the twenty fourth feature is modified in that the sub substrates are separated from each other with the use of a rotary blade which is also adapted for roughing the sides of the shielding case. This eliminates an extra step for preparing the roughed surface, hence improving the productivity.
As a twenty sixth feature of the present invention, the method of producing high-frequency modules according to the twenty first feature is modified in that a step of engaging pins of an inspection tooling in direct contact with signal terminals of the sub substrate to conduct an inspection is provided between the second step and the third step. The sub substrates can be processed up to the final electrical inspection while they are in the worksheet form, as compared with such a troublesome step of separating sub substrates and then aligning them again for the inspection, hence improving the productivity.
As a twenty seventh feature of the present invention, the method of producing high-frequency modules according to the twenty first feature is modified in that the shielding case is fabricated by punching a sheet of material with dies, bending the sheet in the direction of punching to form bends, and soldering the distal ends of the bends or legs to the grounding terminals provided on the side edges of the sub substrate. The punching forms such burrs on the shielding case as creating a clearance between the shielding case and the grounding terminals. The clearance is thus filled thoroughly with solder due to the effect of capillary action, whereby the resistance to conductivity will be minimized and the bonding strength will be increased. Also, the burrs are formed inwardly of the side edges of the sub substrate, hence minimizing the distance between any two adjacent sub substrates and decreasing the loss of sub substrate materials.